Alkaline zinc-based flow battery: chemical stability, morphological evolution, and performance of zinc electrode with ionic liquid

Abstract

Zinc-based flow battery is an energy storage technology with good application prospects because of its advantages of abundant raw materials, low cost, and environmental friendliness. The chemical stability of zinc electrodes exposed to electrolyte is a very important issue for zinc-based batteries. This paper reports on details of chemical stability of the zinc metal exposed to a series of solutions, as well as the relationship between the morphological evolution of zinc electrodes and their properties in an alkaline medium. Chemical corrosion of zinc electrodes by the electrolyte will change their surface morphology. However, we observed that chemical corrosion is not the main contributor to the evolution of zinc electrode surface morphology, but the main contributor is the Zn/Zn²⁺ electrode process. The morphological evolution of zinc electrodes was controlled by using ionic liquids, 1-ethyl-3-methylimidazolium acetate (EMIA), and 1-propylsulfonic-3-methylimidazolium tosylate (PSMIT), and the electrode performance was recorded during the morphological evolution process. It was observed that the reversible change of zinc electrode morphology was accompanied by better electrode performance.